Drying oil manufacture



Patented Dec. 3, 1946 DRYING OIL Alexander Schwarcman, Buflalo, N. Y.,asaignor to Spencer Kellogg and Sons, Inc., Buffalo, N. 2., acorporation of New York No Drawing. Application February 12, 1943,Serial No. 475,852

12 claims. (on. zoo-404.8)

This invention relates drying oils having improved characteristics fromfatty oils, including drying and semi-drying vegetable oils, and marineoils,,wherein a fatty oil,-

such as linseed oil, is caused to react with a minor amount ofpolyhydric alcohol, advantageously glycerine, in a proportion from 1 to7 per cent-on the weight of the oil, forming an intergroups, and thisintermediate is reacted with an amount of polybasic acid just sufiicientto esterify the said uncombined hydroxyl groups, the

.polybasic acid also being used in the approximate proportion of ircm 1to 7 per cent on'the weight of the oil; and it also comprises theimproved drying oil obtainable as herein disclosed, this new. oil havingsubstantially the appearance and many of the characteristics ofuntreated fatty oils, but being capable of polymerization in a veryshort time, of drying quickly to a tackfreefllm, and of formingespecially waterproof:

films upon drying; all as more fully hereinafter set forth and asclaimed.

Many of the known'drying oils, including-linseed oils, perllla oil,Shine-wood oil, oiticica oil:

walnut oil, soya bean oil, sunflower oil, poppy to drying oilmanulecture; and it comprises a method of preparing .mediate producthaving uncombined hydroxyl 10 tacky for a considerably longer period.This is a marked disadvantage for many applications,

since a film which remains tacky for any length of, time must beprotected from dust, moisture,

etc., during the drying period, or the coated surface will suflerpermanently. Polymerized oil films have therefore not been widely usedin many applications for which they are well suited, because other typesof filmsdry much more rapidly. This is a great advantage in manyindustries, such as the automobile industry and the furniture industry,where quick drying is highly important. Quick drying is also veryimportant in many other applications; such as lithography and printing,.Where slow drying of the ink causes spoilage, blotting, etc.

An object achieved by the present invention is the production '01polymerized drying oils which dry very rapidly to a dust-free, non-tackyseed-oil, etc., are used in their natural state 7 as drying oils for theproduction of protective or decorative coatings, preferably afteradmixture of a minor amount of catalytic drier, such as compounds ofcobalt, lead, manganese, etc. It is also known that most of these oilscan be polymerized by heating to elevated temperatures, which areusually of the order of 550 to 600 F., and that the viscosity of theoils is thereby increased, and certain other characteristics aremodified.

For some purposes, the, raw or unpolymerized oils are widely used; Thisis often the case in general exterior and interior painting. Thepolymerized oils, such as stand oil, are also widely used in painting,usually after thinning or'reducing them with solvents to the consistencydesired for brushing, spraying, or other methods of application. It iswell known that the polymerized oils have certain advantages over theunpolymerized oils, in that they usually flow better and spread to auniform surface, which does 4. of the after-yellowing eflect,- which isencountered with some raw oils. Furthermore, I

when completely dried, either alone 'or in the presence 01 pigments, apolymerized oil film is dry more slowly than raw oil films, and remaincondition, often equalling in this respect other types of sprayinglacquers. A further object achieved by this invention is the provisionof a polymerized oil which dries to an especially waterproof film. Inaccordance with a yet fur-- ther object there is provided a modifieddrying oil product which is capable oi polymerizing much more rapidlywith an accompanying elimination of adverse side reactions.

These objects and advantageous results are achieved in accordance withthis invention by combining a fatty oil, such as a drying or semidryingvegetable oil or marine oil, with a minor amount, advantageously about 1to "l. per cent by weight, of a polyhydric alcohol, such as for exampleglycerine. The oil and glycerine are agitated together at an elevatedtemperature, usually between 400 and 500 F., :until reaction is completeand the free glycerine has disappeare'd. The time required for thisoperation varies with the quantity of the materials treated,from'sev'eral minutes to one hour or more. The time may 'be shortenedand the operation conducted more emc'iently by introducing a smallamount of catalyst. It is well known that lith-' ester of glycerolcontaining some free or uncombined hydroxyl groups. To this product isadded,

in substantially the stoichiometric al proportioncorresponding to thepolyhydric alcohol introduced, a polybasic acid, and themixture isheated with agitation until esterificatlon occurs. Any of the varioustypes of polycarboi'rylic acids may be used for this purposeandespecially advantageous results are obtained when using maleic acid orfumaric acid. Of course the anhydrides of the foregoing acids areequally suitable and out disadvantage.

and to maintain it for a very short time. I of the advantages of thisproduct is that it poly- 3 may be substituted for the respective acidswith- I Phthalic acid and its anhydride, when emplo ed in this step orthe process, likewise results in materially improved product.

Advantageously the amount of polycarboxylic acid employed correspondsapproximately, to that required for complete esteriflcation of the' polyhydric'alcohol added in the preceding step. In other words, the relativeamounts of polyhydric alcohol and acid employed are preferablyproportioned so as to substantially completely esterify all of theavailable alcoholic and carboxylic acid groups introduced. This resultis conveniently attained by continuing addition of the polycarboxylicacid or its anhydride until a product of low acid number results. Theapproximate relative quantities of reagents required to complete thereaction are equivalent to the stoichiometrical proportion of thealcohol and acid required for complete esteriflcation. This, therefore,forms a good approximate index of optimum proportioning. While theadvantages of the present invention are secured with some variation fromop- .timum procedure, it is, however, desirable in all cases toapproximate the final condition of low acid value desirable in dryingoil of the present drying oil having very low acid number and exeellentdrying properties. The material may be sold and used as such, but isadvantageously polymerized before use. Polymerization may be effected bythe manufacturer, or as a separate process' conducted by the purchaser.It is generally most economical to polymerize immediately, since allthat is required for this purpose is to raise the temperature to thebodying range, which is usually somewhat above the reaction temperature,One

merizes so much more rapidly than the oils used as starting materials.This is highly advantageous, since the loss of oilduring polymerizationand the development of acidity are usually functions of the timerequired for polymerization. In hodying ordinary linseed oil, a time onthe order of five hours or more is generally required to bring the oilup to a viscosity of 2-6 on the Gardner-Holdt scale. During thistreatment there is a'ssubstantial loss of oil,- and the acidity mayincrease to 8 or 10 per cent. In contrast, the same body may be obtainedin an oil treated as described hereinabove, by heating for considerablyless than one houroften in 30 to 40 minutes. Under these conditions, theloss of oil during polymerization is negligible, and the acidity doesnot increase beyond 1 or 2 per cent.

Further advantages of the product are that after polymerization, it willdry to .a dust-free film in four hours or less, as compared with 48hours or more for the ordinary polymerized linseed oil. Furthermore?when dry, it forms a film of great y increased resistance to moisture,or waterproofness. In this-respect, the improved'oil of this inventionmore closely resemblesu China-wood oil than the polymerized linseed oilavailable heretoore.

The process by whichthis improved 11 is 0b- 4 tained can be performed inthe open at atmospheric pressure. The operations can alsobe performedunder vacuum, and this is often advantageous, since it makes it posibleto obtain a lighter colored product. It is well known that the presenceof atmospheric oxygen during treatments at high temperatures generallyhas a tendency to darken fatty oils, and this is true in the presentcase. Operating under vacuum, or in an 19 atmosphere of inert gas,prevents this.

In a typical embodiment of this invention, 1900 pounds of linseed oiland 70 pounds of glycerine (3.7 per cent by weight) were mixed togetherwith 0.6 pound of litharge, to serve as a catalyst. The

1 mixture was agitated while the temperature was raised to 440 F., andthis temperature was maintained until the free glycerine, which hadoriginally floated on the surface, disappeared. A sample of the mixturetaken at this stage was com- 20 pletely transparent and homogeneous. Theheating required about forty minutes at the attained temperature in thisinstance.

The compound thus obtained, consisting principally of combinations ofgiycerine with linseed oil acids with the glycerine present in excess,was further agitated, and about 132 pounds of fumaric acid were added.The temperature was brought up to 520 F., at which time there was astrong discharge of water, indicating that esteriilcation was takingplace. After the water was completely discharged and the oil becameclear, the agitation was stopped.

At this stage, the product could be withdrawn for use or sale, ifdesired. However, in this instance, the temperature was brought up to590 minutes. At that time, a polymerized oil having a viscosity of Z-6on the Gardner-Holdt'scale was obtained.

After cooling, the oil was tested, and found to have an acid numberbetween 2 and 3. A sample of the oil was subjected to a drying test andfound to lose its tackiness in about two hours and to form an extremelywaterproof film.

In another embodiment 01' this invention 1500 pounds of soya bean oilwere heated to about 300 F., 45 pounds of glycerine (3 per cent byweight) were added while stirring, and the temperature 5 was brought upto 430 F. and held for one half hour. The temperature was then raisedto480 F. and held there for another half hour until the oil was entirelyclear and no more vapor was estraces of the acid were combined, giving aprod:

not of very low acid value. During the two stages,

- namely, the combination with glycerine and the csflsteriflcation withacid, a current of inert gas (such a nitrogen orcarbon'ic acid) waspassed through the oil or into the space above the oil,

to eliminate oxidation and darkening.

At this stage the oil was somewhat heavier than v the original oil andcould be used as such, but

the heating was continued at560 F. and the consistency increased veryrapidly to 2-6, reaching this viscosity in about one-third the timerequired to polymerize the original oil to this extent. By the sameprocedure, exceptionally good resultsv F., and maintained at that pointfor about forty we're obtained with marine oils, such as menhaden oil.

Similar operations were also conducted under vacuum with similarresults, except that a somewhat lighter colored product was obtained.Also. various other oils of the type previously mentioned were treatedin a similarmanner with similar results. As noted, exceptional resultswere obtained in the treatment of marine oils, such as sardine and,menhaden oils, in accordance with the method described. It is wellknown that these marine oils contain only a minor proportion of dryingconstituents (clupanodonic esters) and a preponderance of non-dryingesters which ordinarily prevent satisfactory drying of these marine oilswhen used alone. For this reason,

- decreased addition of acid will result in a roduct 1 marine oils aregenerally used only in admixture with other oils having better dryingproperties. I have found that by treating these marine oils withminor'amounts of polyhydric alcohols, such as glycerine, and polybasic'acids, such as maleic and especially fumaric acid, as describedhereinabove, it is possible to convert marine oils into oils havingexcellent drying properties.

While the foregoing examples have been presented with glycerine as theillustrative polyhydric alcohol, the invention is not so limited butcontemplates the utilization of any alcohols coming within the field ofpolyhydric alcohols. Thus, products having the improved and advantageouscharacteristics sought by the present final drying oil possessessuperior drying qualities.

forms especially waterproof films and polymerizes even more rapidly.Thus, where the erythritols as; for example, penta-erythritol, areemployed, bodying" 'suflicient for most purposes takes place merely uponheating the product to the bodying range. Polymerization is thussumciently rapid to materially inhibit side reactions and the formationof undesirable products as pointed out above.

Similar results are characteristic of processes employing even higherpolyhydric alcohols as, for example, the hexahydric alcohols, sorbitoland mannitol.

In accordance with an embodiment of this invention employing a dihydricalcohol, 14250 pounds of linseed oil were heated to about 450 F. 630pounds of propylene glycol were added slowly with stirring over a periodof abouttwo hours. The temperature during addition was kept within450-500 F. At the end of this time the mass of oil was clear andhomogeneous. 812 pounds of maleic anhydride were slowly added and thetemperature was brought slowly to 540 F., at which time there was astrong discharge of water vapor. After discharge of. the vapor hadceased and the oil became clear, agitation was stopped. In thisembodiment about three hours were required to complete additionof allthe maleic anhydride and completion of the reaction. The product of theforegoing treatment possessed an acid number or The product may,however, be varied in accordance with the acid number desired orpermissible for the purpose intended, although as indicated above it isusually desirable to produce a product having a' low acid numberapproximating zero. A slightly of lower acid number. It will be apparentthat the quantity of polycarboxylic acid necessary to complete thereaction may be readily determined ture was brought up to about 540 F.Samples tested indicated anacid number of 2-3, whereupon agitation wasstopped. The product as indicated above was particularly valuable inthat. it was capable of being l illymerized to a 2-2 body by merelybringing it to a temperature of Even greater quantities of thepolyhydric. alcohol and polybasic acid may be employed withsatisfactorily resulting improvement. Thus, in

the foregoing example 600 pounds oi. penta-erythritol may be employedand 864 pounds of the maleic anhydride. portions may be used withresults that are still quite advantageous. For example, a good com-.mercial product results when only 280 pounds of penta-erythritol and 403pounds of maleic anhydride are utilized in the above embodiment. Asindicated above. the advantages of the present invention are in eachinstance noticeable down "to and including quantities approximating oneper cnt of the amount of oil used.

In an embodiment illustrating the use of the hexahydrlc alcohols 9300pounds of linseed oil were heated to about 300 F. and 350 pounds ofmannitol added slowly while heating to about 480 F. When the roduct wasclear and homogenenus the temperature was raised to: about 540 F. and565 pounds of maleic anhydride were slowly added with stirring until theacid value became very low. By this procedure a product of ouiteimproved character was obtained. Similarly good results were obtainedwhere sorbitol was substituted for the mannitol above.

As previously stated, I find it most advantageous to employ about 1 to 7per cent each of glycerine and the polybasic acid in the process of thisinvention. Smaller quantities of these constituents do not give. thoptimum results,

although they generally efi'ect some improvement; Larger quantities,materially exceeding about 1 to 7 per cent of the glycerine and theequivalent amount of poiybasic acid, do not improve the quality of thetreated oil, and therefore the expense of larger quantities is seldomjustified.

As stated above. the glycerine or other polyhydric alcohol and thefumaric acid, or other pclybasic acid or anhydride are employed insubstantially stoichiometrical proportions so that a substantiallyneutral product is obtained. Ii desired. however, a slight excess ofglycerine may be employed to neutralize the acidity which some timesdevelops during high temperature treatment. Also, it is sometimesadvantageous to add is generally made suiiicient to-in'surc that aneutrahsubstantially acid-free product'is obtained.

76 In. any .case, as previously noted. the finished On the other hand,lower pro- 7 product has substantially the appearance of an oil of thetype used as a starting material, when polymerized to the sameviscosity. It differs from the starting oil chiefly in its rapid dryingcharacteristics and the waterproofness of the film formed therefrom. Inmany instances, as with marine oils, the odor of the oil issubstantially improved by the treatment. Also, the unpolymerized oilobtained in accordance with this invention differs. from the originaloil in being capable of much more rapid polymerization.

It will be noted that in the foregoing illustrative embodiments some ofwhich are carried 'out at the limits of the stated range, the proportionof polycarboxylic acid utilized may vary somewhat from the proportion ofthe polyhydric alcohol. As will be understood from the above thisfollows from the stoichiometricai relationship necessary to form theoptimum product having-a low acid .number. .It will be furtherunderstood that in preparing such products the ,stoichiometric'alproportion of 'polycarboxylic' acid which is approximately suflicient toesterify .the free hydroxyl groups introduced, without any appreciableexcess of carboxylic groups will depend upon the relative molecularweights of the reactants and their molar combining ratio. Ac-

cordingly while the range of 1 to 7 per cent is.

relatively critical in the case of the polyhydric alcohol it isrelatively less critical as applied to the polycarboxylic acid andrepresents more of. an approximation in preparing oils of optimum dryingoil fatty acid may be reacted with a polyhydric alcohol with the latteringredient in excess. The excess of polyhydric alcohol should amount tofrom about 1 to 7 per cent on the weight of the total amount of thereactants which are theoretically required to produce a 1 completelyesteriiled oil. The resulting product may then be reacted with aquantity of polycarboxylic acid stoichiometrically corresponding to theamount of hydroxyl groups theoretically present in the oil; As in theearlier described process. the amount of polycarboxylic acid accordinglyfalls within the approximate range of 1 to 7'per cent onthe amount ofthe oil ester present. Advantageeusly, however, the quantity ofpolycarboxylic acid employed is suillcient groupspresent in the reactionIt be apparent from the foregoing thatbythetermpolybasicacidasusedinthepresenttlmismeantpolybasicorganicacids. M 7. the so-calied polycarboxylic acidsand their obvious equivalents such as the acid anippi cetion is acontinuation-inor mllcatim N0. 392L555, flied m. While my inventiondescribed with to certain 8 h thereof which are -now'consideredespecially advantageous, the scope of the invention is not limited tothese specific embodiments and i'ea-' tures except as indicated in thepended claims.

WhatIclaim is:

1. A process of manufacturing improved drying oils capable of bodyingrapidly to a fast drying product, which comprises heating a fatty oil 10having drying properties with approximately from 1 to 7 per cent on theweight of the oil of a polyhydric alcohol until reaction issubstantially complete and esterifying the reaction product withapproximately 1 to 7 per cent on the weight of the oil of a polybasicacid of the class consisting of polycarboxylic acids and theiranhydrides, to form an oil of low acid number.

2. The method of claim 1 wherein the polyhydric alcohol is glycerine. 1

3. The method of claim 1 wherein the. polybasic acid is maleic acid.

4. The method of claim 1 wherein the polybasic acid is fumaric acid. I

5. The method of claim 1 wherein the polyas hydric alcohol ispenta-erythritol.

6. The method of claim 1 wherein the fatty oilissoya beanoil. f v

7. The method of claim 1 wherein the fatty oil is linseed oil. a

80 8. The method-of claim 1 wherein the fatty oil is manhaden oil.

. the step of heating the esteriiid product to a temperature ofapproximately from 550 to 600 F. to develop the desired viscosity.

10. A process of manufacturing improved dryingjoils capable of bodyingrapidly to a fast drying product which comprises heating a fatty oilhaving drying properties with approximately from .1 to 7 per cent on theweight of the oil of a polyhydric alcohol until reaction issubstantially complete and reacting the reaction product with an amountof polycarboxylic acid falling within the range of approximately 1 to 7per cent on the weight of the oil and Just suiilcient to form a productof low acid number.

11. A process of manufacturing improved drying oils capable of bodyingrapidly to a fast drying product, which comprises heating a fatty oilhaving drying properties with approximately from 1 to 7 per cent on theweight of the oil of a polvhydric alcohol until reaction issubstantially complete and esterifying'the reaction product with apolybasic acid of the class consisting of polycarboxylicacids and theiranhydrldes. said acid being added in approximately that combiningproportion just suilicient to esterify all of the free hydroxyl groupspresent in the reaction. mixture and to form an oil of low 9 we number.

12. A process of manufacturing improved dryin: oils capable of'bodyingrapidly to a fast drying product which comprises heating a fatty oilhaving drying properties at a temperature approximating 450 to 500 c.with about a per cent of glycerine until react-ion is substantiallycomplete and esterifying the reaction product at. a temperatureapproximating 540 F. with a polyblsic acid of the consisting ofpolycarbonlic acidsand their anhydrides, said acid being added inapproximately that combining proportioniustsuiiicienttoesterifyallofthe-freehydiwlgroumpresentinthereactionmixture and to 1am an oilot'low'acid number.

ALEXA-NOB SCHWARCMANL 9. The method of claim 1 to which is added

